Pool Winterization Calculator

Calculate the chemicals and supplies needed to winterize your pool including shock, algaecide, antifreeze, and cover sizing.

Inputs

Pool Volume

gal

Current Chlorine

ppm

Current pH

Current Alkalinity

ppm

Pool Type

Tab to move between fields

Results

Shock Chlorine

1.88 lbs

≈ 8 sticks of butter

Winter Algaecide24 oz

Pool Antifreeze6 gal

Approx. Cover Size521.2 sq ft

Estimated Chemical Cost$62.72

How to Use This Calculator

Enter your pool volume in gallons — use the Pool Volume Calculator if needed.
Input the current chlorine level, pH, and total alkalinity from a recent water test.
Select pool type: 1 = inground or 2 = above-ground to determine cover sizing.
Review Shock Chlorine Lbs and Algaecide Oz — add these quantities the evening before closing.
Check Antifreeze Gallons needed for line protection if you are in a freeze-prone climate.
Use Cover Size and Total Chemical Cost to prepare your winterization supply list.

How the result changes with Pool Volume

Pool Volume	Shock Chlorine
10,900	1.36 lbs
35,650	4.46 lbs
65,350	8.17 lbs
90,100	11.26 lbs

What each input means

Pool Volume: Total pool water volume in gallons.
Current Chlorine: Current free chlorine level before winterizing.
Current pH: Current pH level (adjust to 7.2-7.6 before closing).
Current Alkalinity: Current total alkalinity (adjust to 80-120 ppm before closing).
Pool Type: 1 = Inground, 2 = Above Ground.

How this is calculated

Worked example, using the default values

Identify Input Parameters
4 parameters
Pool Volume = 15000, Current Chlorine = 2, Current pH = 7.4, Current Alkalinity = 100 = 5 input(s) provided
Calculate Shock Chlorine
Shock Chlorine
1.88 = 1.88
Calculate Winter Algaecide
Winter Algaecide
24 = 24
Calculate Pool Antifreeze
Pool Antifreeze
6 = 6

Engine last updated July 11, 2026. Checked against 2 independently-derived tests — how we verify calculators.

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